THE NUTRITIONAL NEED OF ADOLESCENTS
Dr. Ranjana Chatterjee*
Prof. & Head Department of Pediatrics N R S Medical College, Kolkata *
What is adolescence?
Adolescence is often defined as a transient stage, between childhood and adulthood, and a formative period during which many life patterns are learnt and established. It is a crucial and dynamic time for young people as they begin to develop their capacity for empathy, abstract thinking and future-time perspective; A time when the close and dependent relationships with parents and older family members begin to give way to more intense relationships with peers and other adults. It is a time when physiologically adolescents begin to reach their adult size, their bodies become more sexually defined and reproductive capacity is established.

The concept of adolescence itself is in relatively new. Until the twentieth century, the passage from childhood to adulthood occurred relatively quickly, usually coinciding with puberty and subsequent child-bearing. More recently, both biological and socio-economic landmarks bracketing the transition to adulthood have moved in opposite directions. Menarche occurs earlier and many societies' adjusted definition of social and economic maturity and independence has moved upward in the ten years. As a result, adolescence can no longer be viewed merely as a stage between adulthood and childhood. It is now a unique and important developmental period requiring specific programming and policy attention.

How big is the problem of malnutrition in adolescents?
There are 1.2 billion adolescents aged 10-19 in developing nations, making up one-fifth to one quarter of their country's populations. Adolescents have typically been considered a low-risk group for poor health, and often receive few healthcare resources and scant attention. However this approach ignores the fact that many health problems later in life can be improved or avoided by adopting lifestyle habits in adolescence.

Main nutritional issues for adolescents:
The world's adolescent population faces a series of serious nutritional challenges not only affecting their growth and development but also their livelihood as adults. Yet adolescents remain a largely neglected, difficult-to-measure and hard-to-reach population, in which the needs of adolescent girls in particular are often ignored.

Adolescence is the second most critical period of physical growth in the life-cycle after the first year. Adolescence is a particularly unique period in life because it is a time of intense physical, psychosocial and cognitive development. Increased nutritional needs at this juncture relate to the fact that adolescents gain up to 50% of their adult weight, more than 20% of adult height and 50% of their adult skeletal mass. During this period, Caloric and protein requirements are maximal. Increased physical activity, combined with poor eating habits and other considerations, e.g., menstruation and pregnancy, contribute to accentuating the potential risk for adolescents of poor nutrition.

Adolescence Diet:
Adolescents require the highest amount of nutrients during the height of their growth.

Studies on nutritional requirements are limited because they do not take into account both age and physical activity, the Recommended Dietary Allowances (RDA) only take into consideration age, not physical maturity. It is known that nutritional requirement during this time is high, however, boys grow the fastest during the age of 12½ to 15½ years, while the growth spurt of girls is at a slightly younger age usually 10½ to 12½ years of age. A healthy diet for teenagers should be based on as wide a variety of foods as possible, with an emphasis in foods of high nutrient density - food from the main four groups. Sometimes it seems as though the adolescents eat in excess, but in reality they only eat until they feel full and these large amounts of food are needed to fill the demands for growth and they should usually surpass the amount of energy that is consumed. According to a study done from 1989 - 1991 by NHANES III the diets of adolescents:
  • Meet the demands for protein - protein in adolescents diets account for 13-14% of total energy intake. Fail to meet RDS for certain minerals (Zn, Ca, Fe) in females. Males, however, consume diets supplying 95% RDA.
  • Seem to meet RDA for vitamins except vitamin A and E. Vitamins A, B-6, C and folate may be limiting during adolescence.
Minerals and Vitamins needed During Adolescence
The protein, which teens need, is essential for satisfactory growth and mending of boys tissues. The recommendation is that the energy value of the protein intake should make up 7% to 8% of the total energy consumed. The average range of protein is between 39 to 56 grams, but this amount can usually be obtained through regular diets so protein intake shouldn't be over emphasized. The best quality sources of protein come from animal products such as meat, fish, and dairy products. Because animal products are the best sources of protein, vegetarian diets are not suggested at this growth stage unless under the supervision of a qualified health professional.

Surveys of adolescents, both athletes and the general population, show that sufficient amounts of protein are consumed but carbohydrate intake may be somewhat low and fat intake somewhat high. The proportion of protein, carbohydrate and fat in the diet should be about 12-15%, 55-60%, and 25-30% of total calories, respectively.

The important mineral that is needed at this stage of development is Calcium. The calcium requirements are higher during adolescence because it is a time of bone growth. The total amount of calcium recommended is the same for both males and females. The best source of calcium is dairy products. A pint a day of any type of milk or its equivalent in cheese or yogurt will provide a good proportion of calcium teenagers need each day. Skimmed and semi-skimmed milks are lower in fat and calories than whole milk but they contain all the protein, calcium and most of the vitamins, like all dairy products low fat dairy products such as low fat and 'diet' varieties of yogurt and reduced fat cheeses are good sources of calcium.

Besides calcium and protein, adolescents also need iron. Adolescent females require more iron than kids do because they lose iron monthly with the beginning of menstruation. Because females lose blood through menstruation, iron deficiency is often a problem. Males, on the other hand, need more iron because "of the buildup of muscle mass, accompanied by greater blood volume". In order to prevent an iron deficiency the source and quality are important. About 27% of adolescents are estimated to be anemic in developing countries, compared to 6% in developed one. Unlike the adult population where anemia commonly affects women, adolescent anemia prevalence rates are much more similar between males and females. Anemia is a critical health concern for adolescents because it affects growth and energy level.

The last important mineral for teens is Zinc. Zinc is known to be essential for growth as well as sexual maturation and therefore of great importance in adolescence. The retention of zinc increases especially during the growth spurt leading to more efficient use of the nutrient in the diet. Zinc deficiency may cause growth faltering and delayed puberty. Other minerals that do have importance are magnesium, iodine, phosphorus, copper, chromium, cobalt, and fluoride.

One last concern is fiber. According to the website entitled, "American Health Foundation..," teens aren't getting enough fiber to ward off diseases and chronic illnesses, according to research by the Experimental Biology 97 scientific meeting in New Orleans. The minimum amount of fiber recommended daily is the child's age plus 5 grams of fiber (American Health Foundation).
Causes of Deficiencies
There are changes in eating habits in adolescence that cause the lack of minerals and vitamins and this is due to many things. One of these is skipping one or more meals mostly due to time constrictions. According to Nutrition Throughout the Life Cycle, "the number of meals teenagers miss and eat away from home increases from early adolescence to late adolescence, reflecting the growing need for independence and time away from home". The nightly meal is the one that is eaten most regularly, but females are found to skip this meal, as well as breakfast and lunch, more so than males.

Breakfast is probably the most important meal of the day and most frequently missed. It does not really matter what the breakfast is as long as it contains 300 kcal and an assortment of nutrients. A likely reason for why females miss breakfast more often than males is they are more likely to be concerned with appearance and dieting and they feel that they will regulate their weight by skipping breakfast. This works to the opposite effect because by mid-day they are so hungry that they eat more than if they would have eaten something in the morning. It is hard to get all of the nutritious foods they need if they eat only one meal a day.

Other reasons for adolescents' nutritional problems, revealed by surveys found in "Concerns about the Adolescent Diet" were:
  • fat phobia' among adolescent girls skipping one or more meals - time limitations inappropriate choice of snack foods limited, or no consumption of milk
  • introduction of alcohol consumption.

The other influences that affect eating behavior are the independence of being in their own and starting to prepare and buy more of their food by themselves, advertising, the easiness of getting ready to eat foods, and the nutritional limitations of fast foods.

To meet their growth needs, adolescents require higher intakes of some vitamins than those for adults. The need for riboflavin is higher because of increased energy intake, but intake is frequently low in teens, especially in girls. Folate and vitamin B12 needs are increased because of the high rates of growth Vitamin B6 is essential for the protein synthesis that occurs during rapid growth. The intake of this vitamin is often low in girls. The needs for calcium, iron, and zinc increase substantially during the adolescent growth spurt. All three of these minerals are frequently deficient in the adolescent diet.

Though the need for calcium and iron can't be emphasized enough, other micro-minerals should not be ignored. In physically active children, the recommended dietary allowances (RDA) for zinc and the safe intake levels for chromium are not increased, but the intakes of these two minerals tend to be low. The current RDA for zinc is 10 milligrams for children and 15 milligrams for adolescents; the estimated safe and adequate daily dietary intake for chromium is 50-200 micrograms. Young athletes are encouraged to increase their energy intake by consuming foods rich in zinc (e.g., shellfish, especially oysters; meat, eggs, wheat germ) and chromium (e.g., meats, unrefined food, whole grains, cheese). This will help ensure that they meet their needs.

More and more teenagers are choosing not to eat meal, fish or poultry. They are becoming vegetarians. Probably the most frequent questions for teenage vegetarians are about the nutritional adequacy of their food choice. The key to a healthy vegetarian diet is variety. It includes fruits, vegetables, plenty of leafy greens, whole grain products, nuts, seeds and legumes. It is not necessary to plan combinations of foods to obtain enough protein or amino acids. A mixture of plant proteins eaten throughout the day will provide enough essential amino acids. Vitamin B12 is a vitamin which only vegans (vegetarians eating no dairy, eggs, meat, fish, and birds) need to add to their diet. Teenagers sold on vegetarianism will need to maximize their absorption of non-heme iron. Vitamin C will enhance absorption of iron in the diet. Tea, coffee, and foods with the preservative EDTA (e.g., fats and soft drinks), will inhibit absorption. Therefore, rather than drinking coffee with cereal, teenagers should drink orange juice. Milk should be consumed to provide not only calcium but also vitamin D. Milk is fortified with vitamin D, which plays a major role in calcium metabolism. Even when cheese and yogurt are eaten, less milk will mean less vitamin D.

In summary, the main nutrition problems affecting adolescent population worldwide include:
  • Under-nutrition in terms of stunting and thinness, catch-up growth and intrauterine growth retardation in pregnant adolescent girls. Iron deficiency and anemia Iodine deficiency Vitamin A deficiency Calcium deficiency Other specific nutrient deficiencies, e.g. Zinc, folate
  • Obesity.

Strategies can be taken to improve adolescents nutritional status:
  • Improving knowledge among boys, girls, parents, school teachers and other community members about nutrition and the causes, symptoms and consequences of under nutrition or specific deficiencies such as anemia, as well as symptoms of eating disorders through health education programs in schools, health facilities, community outreach, and media and public information campaigns. Dietary Intake: Working with adolescents and their families to improve dietary intake such that adolescents are able to meet a maximum of their nutritional requirements through locally available and culturally appropriate foods. Supplements: Where adolescents are at risk and where dietary intake alone is not enough to fulfill certain nutrient requirements, such as iron, initiate supplementation and or food fortification programs. Anemia Prevention: Where intestinal parasites are prevalent, initiate treatment programs for boys and girls to help prevent anemia. Reproductive Health: Initiate programs to reduce unwanted pregnancy and sexually transmitted infections (to reduce risk of anemia and interference with healthy growth) and improve birthing, abortion and post-abortion care (to reduce risk of anemia). Life Skills Education/Youth Development: Integrate nutrition, messages into health promotion components of youth development and life skills education programs (both in-school and out-of-school), which typically focus in improving self-image and self-worth of adolescents.
  • Primary Care: Work with primary care providers to recognize symptoms of diagnosis, treat and provide referral for the problem.
Recommended dietary allowances:


Sex / Age Vit. A (RE) Vit. D (µg)

Vit. C (mg)

Calcium (mg)

Iron (mg)

Zinc (mg)

Male

11-14 1000 10

50

1200

12

15

15-18 1000 10

60

1200

12

15

19-24 1000 10

60

1200

10

15

Female

11-14 800 10

50

1200

15

12

15-18 800 10

60

1200

15

12

19-24 800 10

60

1200

15

12

References :
  1. Geng, FJ and Heald, FP (1994). Diet, nutrition, and adolescence, In: Modern Nutrition in Health and Disease, 8th edn. Shils, MA, Olsen, JA, and Shike, M, Eds, Philadelphia, Lea & Febiger, pp 7759-7769.
  2. Delisle H, Chandra-Mouli MD and de Benoist B. Should adolescent be specifically targetted for nutrition in developing countries: To address which problems and how?
    Who:http://who.int/child-adolescent-Health/New Publications /NUTRITION/ Adolescent Nutrition. Paper.pdf (posted in 2000)
  3. Concerns about the Adolescent diet -
    http://ets.cac.psu.edu/projects/Nutrition/Children/adolcon.html (23 April 1998) searched on 07.10.05.
  4. Nutritional needs During Adolescence"
    http://ets.cac.psu.edu/projects/nutrition/children/adolneed.html (23 April 1998) searched on 07.10.05.
  5. Vegetarian Nutrition for teenagers"
    http://vegsoc.wellinton.net.nz/teen.html
    (23 April) searched on 07.10.05.
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